title: Multicenter, prospective clinical evaluation of respiratory samples from subjects at risk for Pneumocystis jirovecii infection by use of a commercial real-time PCR assay.
abstract: Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection. Microscopic diagnosis, including diagnosis using the Merifluor-Pneumocystis direct fluorescent antigen (MP-DFA) test, has limitations. Real-time PCR may assist in diagnosis, but no commercially validated real-time PCR assay has been available to date. MycAssay Pneumocystis is a commercial assay that targets the P. jirovecii mitochondrial large subunit (analytical detection limit, ≤ 3.5 copies/μl of sample). A multicenter trial recruited 110 subjects: 54 with transplants (40 with lung transplants), 32 with nonmalignant conditions, 13 with leukemia, and 11 with solid tumors; 9 were HIV positive. A total of 110 respiratory samples (92% of which were bronchoalveolar lavage [BAL] specimens) were analyzed by PCR. Performance was characterized relative to investigator-determined clinical diagnosis of PCP (including local diagnostic tests), and PCR results were compared with MP-DFA test results for 83 subjects. Thirteen of 14 subjects with PCP and 9/96 without PCP (including 5 undergoing BAL surveillance after lung transplantation) had positive PCR results; sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) were 93%, 91%, 59%, and 99%, respectively. Fourteen of 83 subjects for whom PCR and MP-DFA test results were available had PCP; PCR sensitivity, specificity, PPV, and NPV were 93%, 90%, 65%, and 98%, respectively, and MP-DFA test sensitivity, specificity, PPV, and NPV were 93%, 100%, 100%, and 98%. Of the 9 PCR-positive subjects without PCP, 1 later developed PCP. The PCR diagnostic assay compares well with clinical diagnosis using nonmolecular methods. Additional positive results compared with the MP-DFA test may reflect low-level infection or colonization.
authors.affiliation: Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland.
authors.forename: Philippe M
authors.initials: PM
authors.lastname: Hauser
authors.forename: Jacques
authors.initials: J
authors.lastname: Bille
authors.forename: Cornelia
authors.initials: C
authors.lastname: Lass-Flörl
authors.forename: Christian
authors.initials: C
authors.lastname: Geltner
authors.forename: Marta
authors.initials: M
authors.lastname: Feldmesser
authors.forename: Michael
authors.initials: M
authors.lastname: Levi
authors.forename: Hitesh
authors.initials: H
authors.lastname: Patel
authors.forename: Victoria
authors.initials: V
authors.lastname: Muggia
authors.forename: Barbara
authors.initials: B
authors.lastname: Alexander
authors.forename: Martin
authors.initials: M
authors.lastname: Hughes
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Follett
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Cui
authors.forename: Flora
authors.initials: F
authors.lastname: Leung
authors.forename: Gillian
authors.initials: G
authors.lastname: Morgan
authors.forename: Adrian
authors.initials: A
authors.lastname: Moody
authors.forename: David S
authors.initials: DS
authors.lastname: Perlin
authors.forename: David W
authors.initials: DW
authors.lastname: Denning
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009172:Mycology / Q000379:methods*; D045363:Pneumocystis carinii / Q000235:genetics / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity